Vostok Ice Core Data
Slide 4 in this series.
Turning to historic temperature data. Over 420K years there is an apparent repeating pattern.
A comparison with the Milankovitch Cycles, consisting of changes in the Earth’s orbit, eccentricity (major component of 413,000 years, with minor components of 125,000 years and 95,000 years resulting in a beat frequency of about 100,000 years), obliquity (changes in axial tilt of about 41,000 years), and axial precession (about 25,800 years), is very compelling. (These changes in orbit and tilt are as a result of gravitational effects from Jupiter and Saturn.)
The periodic pattern cannot be denied The 100K Milankovitch cycle is the reason.
A startling observation can be made. Temperature starts to rise when CO2 is low, and falls when CO2 is high. CO2 actually lags temperature!
NEXT: The Last Glacial Maximum offers us more insights.
These are the topics within the history section.
